The present invention relates generally to therapeutics, and more specifically, to compositions and methods which may be utilized in the treatment and/or prevention of proliferative skin and eye diseases such as psoriasis and proliferative retinopathy.
Proliferative skin diseases such as psoriasis affect as many as 2 to 3% of the entire U.S. population, with more than 250,000 new cases being diagnosed each year. The cost of treating psoriasis in the United States alone is estimated to range between three and five billion dollars per year, thus representing a major health cost to the health care system. Although the cause of psoriasis is presently unknown, there is evidence which tends to suggest that it is a polygenetic autoimmune disorder.
Proliferative skin diseases such as psoriasis are characterized by itchy, inflamed, scaly lesions which bleed easily. Although there are a wide variety of topical treatments (e.g., coal tar preparations, steroid-based creams and ointments) and systemic treatments (e.g., ultraviolet radiation, PUVA, steroids, and chemotherapeutic agents such as methotrexate), at present there is no cure for psoriasis. Further, presently available treatments are generally unsatisfactory, in that remission rates are high and certain therapeutic regimens have potentially serious side effects.
Proliferative diseases of the eye such as proliferative diabetic retinopathy (PDR) affect as many as 700,000 in the U.S., with more than 65,000 new cases diagnosed each year. Annually, as many as 25,000 people go blind from the disorder, making it a leading cause of blindness among working-age Americans. The cost savings from successful intervention could be as high as 100 million dollars per year. The disease does not stem from a single retinal change. Rather, it may be triggered by a combination of biochemical, metabolic, and hematological abnormalities.
There are no early symptoms. There is no pain, no blurred vision, and no ocular inflammation. In fact, many people do not develop any visual impairment until the disease has advanced well into its proliferative stage. At this point, the vision that has been lost cannot be restored. Laser surgery, also called photocoagulation, is the only current therapy to treat PDR. At present there is no cure for this disease.
Scarring is a significant source of disfigurement, pain, and increased medical costs for affected patients. It is the result of abnormal events during wound healing that can result in tissue overgrowth characterized by hyperproliferation of fibroblasts and excessive deposition of matrix. In surgery, scar tissue formation and contraction is a major clinical problem. Likewise, scarring following accidental burning or other injuries or trauma often has serious results, causing impaired function and unsightly aesthetic effects. Currently, there are no satisfactory treatments to prevent scarring.
Thus, a need exists for an effective therapy to treat proliferative diseases (e.g., psoriasis, PDR and scarring). The present invention satisfies this need and further provides other related advantages as well.
Briefly stated, the present invention provides ribozymes and ribozyme delivery systems which are able to inhibit the mechanisms involved in proliferation of cells associated with proliferative skin and eye diseases such as psoriasis, PDR and scarring. Accordingly, the present invention ribozymes are provided which are suitable for treating scarring and proliferative diseases by inhibiting a cytokine involved in inflammation, a matrix metalloproteinase involved in extracellular matrix elaboration, a cyclin, a cell-cycle dependent kinase, a growth factor involved in cell cycle regulation, or a reductase.
Within one aspect of the invention, such methods generally comprise the step of administering to a patient a therapeutically effective amount of ribozyme which cleaves RNA encoding a cytokine involved in inflammation, a matrix metalloproteinase, a cyclin, a cell-cycle dependent kinase, a growth factor, or a reductase such that said proliferative skin disease is treated. Within a related aspect, methods of treating proliferative skin disease are provided comprising the step of administering to a patient an effective amount of nucleic acid molecule comprising a promoter operably linked to a nucleic acid segment encoding a ribozyme which cleaves RNA encoding a cytokine involved in inflammation, a matrix metalloproteinase, a cyclin, a cell-cycle dependent kinase, a growth factor, or a reductase such that said proliferative skin disease is treated. Representative examples of proliferative skin diseases include psoriasis, atopic dermatitis, actinic keratosis, squamous or basal cell carcinoma, viral or seborrheic wart.
Within other aspects, such methods generally comprise the step of administering to a patient a therapeutically effective amount of ribozyme which cleaves RNA encoding a cytokine involved in inflammation, a matrix metalloproteinase, a cyclin, a cell-cycle dependent kinase, or a growth factor such that said proliferative eye disease is treated. Within a related aspect, methods of treating proliferative eye disease are provided comprising the step of administering to a patient an effective amount of nucleic acid molecules comprising a promoter operably linked to a nucleic acid segment encoding a ribozyme which cleaves RNA encoding a cytokine involved in inflammation, a matrix metalloproteinase, a cyclin, a cell-cycle dependent kinase, a growth factor, or a reductase such that said proliferative eye disease is treated. Representative examples of proliferative eye diseases include proliferative diabetic retinopathy, proliferative vitreoretinopathy, proliferative sickle cell retinopathy, retinopathy of prematurity and retinal detachment.
Within other aspects, methods are provided for treating or preventing scarring, comprising administering to a patient a therapeutically effective amount of ribozyme which cleaves RNA encoding a cytokine involved in inflammation, a matrix metalloproteinase, a cyclin, a cell-cycle dependent kinase, a growth factor, or a reductase such that said scarring is treated or prevented. Within another related aspect, methods are provided for treating or preventing scarring, comprising administering to a patient an effective amount of nucleic acid molecule comprising a promoter operably linked to a nucleic acid segment encoding a ribozyme which cleaves RNA encoding a cytokine involved in inflammation, a matrix metalloproteinase, a cyclin, a cell-cycle dependent kinase, a growth factor, or a reductase such that said scarring is treated or prevented. Representative examples of diseases or injuries which cause scarring include keloids, adhesions (e.g., surgical adhesions), hypertrophic burn scars, and trauma (e.g., blunt trauma or surgical trauma).
Cyclins and cell-cycle dependent kinases are directly involved in the check point control of cell division leading to proliferation. Particularly preferred cyclins or cell-cycle dependent kinases include CDK1, CDK2, CDK4, Cyclin B1, Cyclin D and PCNA.
Infection or injury induces a complex cascade of events including activation of the clotting pathway, adherence of immune cells to the endothelium, induction of proliferation and migration of cells into the injury site to rapidly repair the insult. These responses are mediated by certain cytokines and growth factors released from the injured tissue and by hematopoetic cells. Chronic inflammation develops when cytokines and growth factors continue to be produced, resulting in an exaggerated healing response. Particularly preferred cytokines include the inflammatory cytokines interleukin 1 alpha and beta, interleukin 2, interleukin 6, interleukin 8, interferon gamma, and tumor necrosis factor. Particularly preferred growth factors include vascular endothelial growth factor (VEGF), and platelet derived growth factor (PDGF).
Matrix metalloproteinases, along with their corresponding inhibitors, tissue inhibitors of metalloproteinases or TIMP, are involved in the repair of injured tissue. The balance between the proteinases and the inhibitors regulates the pattern and extent of wound healing. Excessive production of MMP or insufficient production of TIMP results in abnormal wound healing. Particularly preferred matrix metalloproteinases include MMP 1, MMP 2, MMP 3 and MMP 9.
Preferably, the ribozyme is a hammerhead or hairpin ribozyme, representative examples of which recognize the target site sequences set forth below and in the Examples. In preferred embodiments, the present invention also provides nucleic acid molecule encoding such ribozymes; further preferably, the nucleic acid is DNA or cDNA. Even further preferably, the nucleic acid molecule is under the control of a promoter to transcribe the nucleic acid.
In one embodiment of the invention, nucleic acid molecules are described which encode the ribozymes provided herein. Preferably, the vector is a plasmid, a virus, retrotransposon, a cosmid or a retrovirus. In one embodiment where the vector is a retroviral vector, the nucleic acid molecule encoding the ribozyme under the control of a promoter, which is preferably a pol III promoter, further preferably a human tRNAVal promoter or an adenovirus VAl promoter, is inserted between the 5xe2x80x2 and 3xe2x80x2 long terminal repeat sequences of the retrovirus.
These and other aspects of the present invention will become evident upon reference to the following detailed description and attached drawings. In addition, various references are set forth herein that describe in more detail certain procedures or compositions (e.g., plasmids, etc.), and are therefore incorporated by reference in their entirety as if each were individually noted for incorporation.